A touch panel is a display device in which an input operation can be performed by directly touching a display screen by hand or with a pen. Since the input operation is performed more intuitively that in the case of a keyboard or a mouse, the touch panels have found wide use in vehicle navigation devices, bank ATM (Automatic Teller Machines), and portable electronic devices such as cellular phones, PDA (Personal Digital Assistants), and game devices.
Meanwhile, further miniaturization and improvement in performance of the aforementioned portable electronic devices are required; with the appearance of near-range wireless adapters such as wireless LAN (Local Area Network) and Bluetooth®, for example, electronic devices (electronics) in which an antenna is mounted on a display surface of a LCD (Liquid Crystal Display Device) touch panel and so on have been developed, and a large number of patent applications relating to such devices have been filed.
For example, a touch panel in which the attenuation of emitted electromagnetic waves is small and a sufficient gain can be obtained (see Patent Document 1), a configuration in which an antenna is incorporated in a display device quipped with a touch panel, without loosing the display quality or antenna capability (see Patent Document 2), and a touch panel equipped with an antenna in which a transparent electromotive film fixedly attached to a lower surface of an upper electrode substrate of a touch panel is also used as a ground plate conductor of a microstrip patch (see Patent Document 3) are known.    Patent Document 1: Japanese Patent Application Publication No. 2004-234270    Patent Document 2: Japanese Patent Application Publication No. 2006-48166    Patent Document 3: Japanese Patent Application Publication No. 2003-280815
However, according to the technique disclosed in the aforementioned Patent Document 1, for example, a fixed transparent electrode is grounded via a capacitor to obtain a low potential in terms of radio frequency. Therefore, when the movable transparent electrode and the fixed transparent electrode come into contact with each other during a touch operation of the touch panel, the movable transparent electrode is also grounded via the fixed transparent electrode. The resultant problem is that radio waves are not emitted to thus malfunction as an antenna.
Further, according to the technique disclosed in Patent Document 2, for example, an antenna is formed on a transparent conductive film, but the problem is that the external dimensions are increased because the antenna is formed outside a position detection unit of the touch panel.
Further, according to the technique disclosed in Patent Document 3, for example, an antenna element is formed on either of the lower surface of the upper electrode substrate and the upper surface of the lower electrode substrate of the touch panel. However, the resultant problem, which is similar to that relating to the technique disclosed in Patent Document 1, is that because the lower surface of the upper electrode substrate and the upper surface of the lower electrode substrate are grounded to perform position detection of the touch panel, the antenna function is lost during a touch operation of the touch panel.